Measuring
the activity that happens inside a cell in a living organism can be
done today. However, the methods used to gain access to the inside of
the cells are relatively crude and destructive. Often accessing the
inside of the cells using today's methods kills the cell within only
a few hours, if the cells survive the initial insertion of
probes.

Scientists at Stanford University have developed a new
nanoscale probe they have dubbed the "stealth probe"
which can monitor the inner workings of a cell without causing damage
to the cell. The probe can be used to capture the signals used by
cells to communicate with each other and to monitor the so called
"digestive rumblings" of the cells as they react to
medications for up to a week.

The breakthrough came when the
researchers developed a nanoscale probe that mimics the natural
gateways within a cell that allows materials in and out of the
cellular membrane according to one of the researchers , Nick Melosh.
The team believes that with some modifications, their stealth probe
could be used to insert medications directly inside the cells of the
human body.

Another possible use would be in interfacing a new
generation of prosthetic limbs with muscles that would allow direct
control of the prosthesis just as the muscles controlled the natural
limb. For instance, the muscles of the chest could be connected to an
artificial arm using the probes.

The team used metal-coated
silicon probes about 600nm long to develop their stealth probe. The
tricky part of the design according to the researchers was developing
a hydrophobic band that could be applied to the probe tip that was
only a few nanometers thick.

Melosh said, "Getting that
hydrophobic band just a few nanometers in thickness was an incredible
technical challenge." The hydrophobic band was a very important
part of designing a functional probe and getting the probe to be able
to transfer materials in and out of the cell.

The probe is an
artificial version of the transmembrane protein gateways that
naturally occur inside cells. Melosh said, "What we have done is
make an inorganic version of one of those membrane proteins, which
sits in the membrane without disrupting it. Now we can envision using
it for doing our own gate keeping."

The next step
in the research is to demonstrate a functional probe in living cells.
The team is currently working with human red blood cells, cervical
cancer cells, and ovary cells from a specific hamster
species.

"Ideally, what you'd like to be able to do is
have an access port through the cell membrane that you can put things
in or take things out, measure electrical currents … basically full
control," said Melosh. "That's really what we've shown –
this is a platform upon which you can start building those kinds of
devices."

"A politician stumbles over himself... Then they pick it out. They edit it. He runs the clip, and then he makes a funny face, and the whole audience has a Pavlovian response." -- Joe Scarborough on John Stewart over Jim Cramer